Embodiments described herein relate generally to electrochemical cells having high rate capability, and more particularly to devices, systems and methods of producing high capacity and high rate capability batteries having relatively thick semi-solid electrodes.
Batteries are typically constructed of solid electrodes, separators, electrolyte, and ancillary components such as, for example, packaging, thermal management, cell balancing, consolidation of electrical current carriers into terminals, and/or other such components. The electrodes typically include active materials, conductive materials, binders and other additives.
Some known methods for preparing batteries include coating a metallic substrate (e.g., a current collector) with slurry composed of an active material, a conductive additive, and a binding agent dissolved or dispersed in a solvent, evaporating the solvent, and calendering the dried solid matrix to a specified thickness. The electrodes are then cut, packaged with other components, infiltrated with electrolyte and the entire package is then sealed.
Such known methods generally involve complicated and expensive manufacturing steps such as casting the electrode and are only suitable for electrodes of limited thickness, for example, less than 100 μm (final single sided coated thickness). These known methods for producing electrodes of limited thickness result in batteries with lower capacity, lower energy density and a high ratio of inactive components to active materials. Furthermore, the binders used in known electrode formulations can increase tortuosity and decrease the Ionic conductivity of the electrode.
Thus, it is an enduring goal of energy storage systems development to simplify and reduce manufacturing cost, reduce inactive components in the electrodes and finished batteries, and increase energy density, charge capacity and overall performance.